WASHINGTON — The Navy on Thursday ordered an in-depth investigation into the Washington Navy Yard shooting and the events that led up to it, including a detailed look at the shooter, his mental health background and whether any adverse information was ever reported to the service about him.

Navy Secretary Ray Mabus outlined the order in a memo describing what will be a parallel investigation to the FBI’s criminal probe. The investigations will address lingering questions about whether the contractor that employed Aaron Alexis warned the military of concerns about his mental stability. Alexis gunned down 12 people in building 197 at the Navy Yard on Sept. 16 before being killed in a shootout with police.

There have been questions about whether the company that employed Alexis, Fort Lauderdale, Fla.-based The Experts, had seen indications that he was having mental health problems. And Navy officials say they can find no record that the company alerted the Navy about such concerns.

Mabus asked Adm. John Richardson to conduct the investigation, including whether Navy policies were followed regarding security clearances, building protection and the emergency response to the crisis. The military often orders similar investigations after significant violent incidents.

The probe is in addition to several broader policy reviews ordered by Mabus and Defense Secretary Chuck Hagel. Those evaluate department-wide programs, while this new probe will be more narrow, digging into the events that unfolded as Alexis packed a sawed-off shotgun into his bag, used his access cards to get on the Navy Yard base and into the building, then roamed the halls gunning down workers as they fled.

Mabus ordered the review to be finished by Nov. 6 and said it must include opinions on the adequacy of Navy policies and how well they were followed.